The present invention relates to a method of protecting a bore in a partition using a fire collar and to a fire collar for use in such a method.
Increasingly, plastics material pipes are used in buildings. Such pipes extend through bores in partitions such as walls, floors and ceilings. In the event of a fire such pipes melt or collapse whereby the bore in the barrier provides a channel for the transmission of the fire or smoke or other products therefrom through that partition.
It is obviously important, in the event of a fire, that partitions remain able to contain the fire for as long as possible and fire collars are increasingly provided to ensure that any channel remaining by the melting or collapse of a plastics material pipe is blocked. Generally, the fire collar comprises a metal collar fastened around a pipe, the collar enclosing intumescent material between the collar and the piping. When fire causes the pipe to melt, it also causes the intumescent material between the collar and the piping. When fire causes the pipe to melt, it also causes the intumescent material to expand. The fire collar prevents expansion outwardly, so that the expansion of the intumescent material is inwardly to fill the void left by the melted pipe. In this way, a physical barrier is formed across the bore in which the pipe was arranged.
However, various authorities, including those in the USA, now require that the physical barrier formed across the bore, for example, by the intumescent material, should be capable of withstanding the force of water from a fire hose. Otherwise, attempts using fire hoses to put out the fire can, in fact, break open the bore through the partition and encourage the spread of the fire therethrough.
Various attempts have been made to provide fire collars which are capable of maintaining a partition fireproof even though a plastics material pipe extending therethrough has melted. Examples of proposed devices are described, for example, in British specifications Nos. 1,513,543 and 1,589,890 and U.S. Pat. Nos. 4,307,546, 4,559,745, 5,257,641, and 5,421,127. However, such prior proposals all require the use of more or less complex mechanical devices which are moved by the collapse of the plastics material pipe, for example, to mechanically position a physical barrier across the bore.